Polymyxin B sulfate is a cyclic polypeptide antibiotic derived from Bacillus polymyxa, supplied as a USP/NF grade material meeting United States Pharmacopeia testing specifications. It is commonly used in pharmaceutical and microbiological applications, particularly for antimicrobial studies and analytical workflows involving Gram-negative bacteria.

This compound exhibits strong bactericidal activity by binding to the lipid A portion of bacterial lipopolysaccharides, disrupting membrane integrity and increasing permeability. Due to this mechanism, polymyxin B sulfate is widely used in studies of membrane biology, endotoxin removal, and antimicrobial resistance.

In laboratory settings, polymyxin B sulfate is utilized in pharmaceutical analysis, microbiological assays, and research involving bacterial susceptibility and permeability studies. It is also applied in sample preparation workflows where selective inhibition of Gram-negative organisms is required.

This material is provided as a powder and is suitable for use in regulated laboratory environments requiring USP-compliant substances.